Carbon spheres can be synthesized and activated, to provide properties useful for electrochemical applications. For example, carbon spheres activated with potassium hydroxide can be combined with a binder to provide an electrode for electrochemical capacitors. However, the capacitive performance of such carbon spheres can be limited, in turn limiting the energy density of the batteries.
U.S. Patent App. Publication No. 2011/0112246 discloses preparation of hydrothermal hybrid material from biomass. The hydrothermal products are used in the as-synthesized state for binding metal ions.